A resectoscope of the type with which the invention is particularly useful is disclosed and claimed in my U.S. Pat. No. 3,835,842 and, as illustrated in FIG. 1 in pertinent part, comprises the elongated tubular sheath 2 which is open at its distal end, and the tube 4 which is concentric with and within the sheath and with it forms an annular space 6 which provides the outflow conduit of the instrument. Within and concentric with and spaced inwardly from the tube 4 is the telescope stem 8 which is engaged and surrounded substantially throughout its length by the supporting tube 10. The space 12 between the tubes 4 and 10 and the telescope 8 provides the inflow conduit of the instrument. The instrument also includes a cutting loop 20 having stem 22 through which an electrically conductive wire 24 extends which protrudes from the distal end of the stem to provide spaced parallel arms 26 which are positioned on opposite sides of the telescope stem and at their distal ends are connected by the depending bare wire cutting loop 28. The proximal part of the stem of the cutting loop passes through a passage 29 in the locking block 30 of the working element and into the movable member 32 of the working element where the wire 24 engages the external electrical connection 34. The passage 29 is conventionally located at the six o'clock position in the block 30 and in the movable member 32 of the working element 32.
At the distal end of stem 22 of the cutting loop there is conventionally provided a preferably cylindrical tube 38 which is connected superiorly to the distal end of the stem and extends longitudinally thereof and surrounds the tube 10 which engages and supports the stem of the telescope, thereby to provide means for guiding the cutting loop in its longitudinal movement as it is reciprocated during the use and operation of the resectoscope. The guide 38 may be modified to provide means for stabilizing and strengthening the arms of the cutting loop, as described and claimed in my co-pending application for U.S. Pat. Ser. No. 219,687 for Stabilized Cutting Loop For Resectoscopes, and in Wappler U.S. Pat. No. 3,752,159. These described parts of the instrument do not form part of this invention.
In the course of a transurethral (TUR) procedure the arms 26 or the depending wire loop 28 of the cutting loop may be damaged, necessitating replacement of the entire cutting loop. In order to do this the sheath is left within the patient and the other part of the instrument which constitutes the working element, is withdrawn from the sheath and the damaged cutting loop is removed and replaced with a new cutting loop. It is very easy to withdraw the damaged loop, but it is very difficult to insert a new loop, as the annular space 12 through which the stem of the loop must be passed to the opening 29 in block 30 is very small and it is difficult to locate the opening as it cannot be seen. A material amount of time is therefore often required to make this blind insertion of the new loop.
It has therefore been the object of this invention to provide means for guiding the stem along and through the annular space 12 to the passage 29 in the block 30 of the working element, so that a new loop may be quickly and accurately put into position when it is necessary to do so.